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81.
 从云南水富县太平乡(4群)和贵州六盘水市盘县(3群)共采集了7群东方蜜蜂Apis cerana样本,每群测定分析15只工蜂,每只工蜂总共有38个测定的形态特征。测定的性状特征数据进行主成分分析,聚类分析和因素分析,并与云南省内其它县东方蜜蜂A.cerana的相关数据进行比较。结果发现,水富东方蜜蜂A.cerana个体较大,体色较浅,贵州六盘水东方蜜蜂A.cerana个体较小, 体色较浅,与云南省内南部东方蜜蜂A.cerana分开,与德钦东方蜜蜂A.cerana形成一个类群。  相似文献   
82.
A province-wide cross-sectional seroprevalence and agroecological risk factor study of Mycobacterium avium subspecies paratuberculosis (MAP) and Neospora caninum (NC) infection among cattle in 100 cow-calf herds in Alberta was conducted. The seroprevalence of MAP in adult cattle was 1.5% across all herds. Using a widely accepted herd test cutpoint of 2 or more seropositive cows out of 30 animals tested, 7.9% of herds were estimated to be infected (95% confidence interval (CI): 2.3-23.4%). Seroprevalence of MAP differed by agroecological region; specifically, cattle and herds in areas with high soil pH (> 7.0), southern latitudes, and arid climates had a moderately reduced risk of infection (P < 0.10). Seroprevalence of NC infection was 9.7% among adult beef cattle province-wide--these levels also varied by agroecological region--with 91.0% of herds infected overall.  相似文献   
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The evolutionary success of planktic calcifiers during the Phanerozoic stabilized the climate system by introducing a new mechanism that acts to buffer ocean carbonate-ion concentration: the saturation-dependent preservation of carbonate in sea-floor sediments. Before this, buffering was primarily accomplished by adjustment of shallow-water carbonate deposition to balance oceanic inputs from weathering on land. Neoproterozoic ice ages of near-global extent and multimillion-year duration and the formation of distinctive sedimentary (cap) carbonates can thus be understood in terms of the greater sensitivity of the Precambrian carbon cycle to the loss of shallow-water environments and CO2-climate feedback on ice-sheet growth.  相似文献   
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For the first time, fig mosaic virus (FMV) was detected in common fig (Ficus carica) trees in Shimane, Japan. These trees exhibited mosaic, ringspots, or distortion, accompanied by chlorosis on leaves and yellow spots on fruits. Some of the symptomatic trees were infested with the eriophyid mite Aceria ficus. The virus was detected based on RT-PCR, followed by sequencing. The amplified 300 base-pair fragments shared 83.5–91.5% identity with the corresponding region of RNA-dependent RNA polymerase gene of FMV isolates previously reported in Turkey, Iran, and Italy.  相似文献   
87.
中国东方蜜蜂的形态学及生物地理学研究   总被引:13,自引:2,他引:13  
 用形态学研究方法对中国的东方蜜蜂(Apis cerana)的形态特征进行研究。东方蜜蜂的标本从中国大陆的34个样点采集而来,这些样点代表了东方蜜蜂在中国大陆不同气候带或地理区域分布的不同类型。 34个点共采集了220群蜜蜂的样,每群蜂测定分析15只工蜂,形态的测定特征参照Ruttner 1988年提出的测定标准进行。每只蜂总共有38个测定的形态特征。测定的性状特征的数据进行因素分析,集合分析和区辨分析;形态性状与生态环境因子相关性分析;并与周边国家东方蜜蜂的相关数据进行比较,发现:生活在吉林长白山温带阔叶林的东方蜜蜂个体较大、体色较黑,与日本、韩国的东方蜜蜂较为相似;来自亚热带常绿阔叶林的东方蜜蜂(甘肃天水、湖北和湖南)与云南北部、北京、尼泊尔的东方蜜蜂聚集为一类;而居住在南方热带季雨林如:福建、广东、广西和云南部分南方的东方蜜蜂与低海拔亚热带常绿阔叶林的东方蜜蜂(越南、中国四川和安徽黄山)聚集为另一类; 云南南方如:景洪、思茅、河口、镇康、元江、屏边、蒙自草坝和开远的东方蜜蜂形成独特的一个分枝,与泰国和缅甸的东方蜜蜂非常接近,同时与亚热带常绿阔叶林的东方蜜蜂相邻;值得关注的是,来自高寒湿地的东方蜜蜂(甘肃岷县)是目前在亚洲已经发现的东方蜜蜂中,其个体最大、颜色最深。在因素分析和集合分析里,它具有独特的位置。  相似文献   
88.
duniperus sabina Linnaeus, an evergreen shrub with prostrate life form, can effectively prevent sand moving and is an important tree species for reforestation in semiarid areas of China. It has laterally distributed adventitious roots and a deeply distributed main root system. To detect water movement between the main root system and adventitious roots, we adopted heat pulse sensors using the Heat Ratio Method, a high precision method for measuring low sap flow rates. Two sensors were implanted in each individual in the stem between the main root system and adventitious roots, and another two in lateral stems distal to all the roots. Positive sap flows during nighttime, even under saturated air moisture conditions, were detected only between the main root system and adventitious roots under drought conditions, and the rate of flow increased as drought progressed and decreased or disappeared after rain events. The results demonstrated the existence of water movement from the main root system to adventitious roots, and combined with the high contribution of nighttime sap flow to transpiration (11%-16%) the results indicate that it also involves the process of hydraulic lift, a water movement from moist subsoil to dry surface soils. Integrated water use strategy between the main root system and adventitious roots via the process of hydraulic lift of soil water maximizes water acquisition efficiency from both subsoil water and water from rain pulses on the soil surface; this increases survivability in the water-limited environment of semiarid areas.  相似文献   
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90.
Energy recovery from a crossflow ultrafiltration (UF) membraneunit employed in order to improve the performance of an anaerobic contact digester for the treatment of brewery wastewater was assessed. The performance of the pilot-scale anaerobic UF membrane system was studied for over 15 months. At steady-state conditions, an organic loading rate of 28.5 kg COD m-3 d-1, a hydraulic retention time of 4.2 days and overall COD and BOD removal efficiencies of 99% and almost 100% were achieved, respectively. Percent methane in biogas was found to be in a range of 67–79% with the corresponding methane yield of 0.28–0.35 m3 CH4 kg-1 CODremoved. The potential energy recovery from the system treating brewery wastewater at an OLR of 28.5 kg COD m-3 d-1 was 87 MJ d-1 which would enable to maintain all energy requirements of the feed pump, mixing and heating of the reactor contents. In addition to this, 71% of the energy requirement for recirculating the reactor content through the membranes would also be recovered.  相似文献   
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